I haven't seen highbush cranberries growing right in swamps, but I've seen them in places that flood with snow melt in the spring.
What height range are you looking for?
Here's a PDF you might find useful: http://centralwashingtonfirerecovery.info/2012/wp-content/uploads/NRCS/WetlandPlantings.pdf
The King County (down in Washington) website has a plant finder, too, and comes up with some good results when searching for "shrub" and "wet": https://green2.kingcounty.gov/gonative/Plant.aspx?Act=search. Here's some of the one's on the list. I bolded the ones I know to be edible. I wonder about the Nootka Rose and blackcap raspberry liking standing water, as they grow naturally on my property in drier places:
bald hip rose, black cap raspberry, black gooseberry, bog laurel, bog rosemary, devil's club (the name really fits it...), highbush cranberry, nootka rose, Pacific ninebark, red-osier dogwood (supposedly edible roots, shoots, stems and seeds), salmonberry, douglas' spiraea/hardhack, stink currant (tastes like pine), subalpine spirea, swamp rose, sweet gale, tall Oregon grape, twinberry
when your children are suffering from your punishment, tell your them it will help them write good poetry when they are older. Like this tiny ad:
Solar Dehydrator Plans - Combo Packagehttps://permies.com/t/74059/digital-market/digital-market/Solar-Dehydrator-Plans-Combo-Package